Large strain hardening in Ti--V carbon steel processed by equal channel angular pressing

摘要

An equal channel angular (ECA) processed low carbon steel containing very fine particles of (Ti,V) nitrides showed significantly larger strain hardening and tensile fracture strain than the ECA processed plain low carbon steel. A ratio of yield strength to ultimate tensile strength, which should be less than 0.8 to satisfy an industry standard requirement for steels in use for structural application, decreased from 0.69 to 0.63 after the first ECA processing in the Ti and V contained steel, while it rather increased from 0.68 to 0.97 in the plain steel. Presence of very fine and strong (Ti,V) nitride particles is believed to be responsible for the high increased work hardening rate in the ECA processed Ti-V steel. The present results indicate that addition of titanium or vanadium to low carbon steel is a very effective way of improving strength as well as work-hardening ability of ECA processed steels.